Why did the Arethusas suit Force K better than Leanders?

Why were the Arethusa-class cruisers better suited to Force K's mission than the Leanders?

The smaller Arethusas were more manoeuvrable and better compartmented, while the Leanders were compromised between cruiser roles.

The Arethusas are assessed as compact, well-rounded light cruisers with useful manoeuvrability and survivability. Their small size suited the confined and aggressive work expected of Force K. The Leanders sat awkwardly between the smaller Arethusas and the more powerful Towns. Weight-saving compromises also left the Leanders with less useful compartmentation.